The present invention relates to an apparatus of feeding cardboards to a carton making section, and more particularly, to an apparatus of feeding cardboards to a carton making section, in the course of which they are individually printed in ink of different colors station by station.
When multi-color printing is carried out on cardboards station by station, it is essential to cause no displacement of the cardboards in transit; otherwise a misprinting will result and spoil the appearance of cartons. However, owing to the warps inherent to the cardboards and a slipping occurring on the conveyor, a misprinting, such as discontinuity of printed lines or stain, often happens. So far no solution to this problem has been found.
In a series of printing process it is sometimes necessary to suspend the operation of some station or others, for example, for repairing or ink-filling. In this case, the printing roller at the station is kept away from the impression cylinder, which means that the feeding path has an inoperative part at which a cardboard, especially a shorter one, is left from feeding. In spite of the fact that there is an inoperative station, the cardboards must be continuously fed.